UNITED NATIONS — The inspectors responsible for tracking down Syria’s chemical arms stockpile and verifying its destruction plan to start work in Syria by Tuesday. They will face their tightest deadlines ever and work right in the heart of a war zone, according to a draft decision obtained Friday by The Associated Press.

The decision is the key to any U.N. resolution on Syria’s chemical weapons program. The five permanent members of the deeply divided U.N. Security Council reached agreement Thursday on a resolution to eliminate Syria’s chemical weapons arsenal, British and U.S. diplomats said, and the full council was set to discuss it Thursday night.

The agreement represents a major breakthrough in addressing the 2 ˝-year conflict, which has killed more than 100,000 people.

Divisions among the permanent members have paralyzed council action on Syria since the conflict began.

U.N. diplomats said this resolution would be the first legally binding one on Syria in the conflict if adopted, which now appears virtually certain.

He said Britain would introduce the text to the 10 other council members Thursday night.

The U.S. and Russia had been at odds on how to enforce the resolution, but Russia’s Foreign Minister Sergey Lavrov and U.S. Ambassador Samantha Power confirmed that the last hurdles to agreement had been overcome.

On Twitter, Power said the draft resolution establishes that Syria’s chemical weapons “is threat to international peace & security & creates a new norm against the use of CW.”

U.S. Secretary of State John Kerry and Lavrov met in hastily scheduled, closed-door talks Thursday afternoon at the United Nations, and the agreement was announced soon afterward.

The agreement came a day after Russia’s deputy foreign minister said negotiators had overcome a major hurdle and agreed that the resolution would include a reference to Chapter 7 of the U.N. Charter, which allows for military and nonmilitary actions to promote peace and security.

The U.S. and Russia had been at odds on how to enforce the resolution to secure and dismantle Syria’s chemical weapons.

The flurry of diplomatic activity is in response to an Aug. 21 poison gas attack that killed hundreds of civilians in a Damascus suburb, and President Obama’s threat of U.S. strikes in retaliation.

After Kerry said Syrian President Bashar Assad could avert U.S. military action by turning over “every single bit of his chemical weapons” to international control within a week, Russia, Syria’s most important ally, agreed. Kerry and Lavrov signed an agreement in Geneva on Sept. 13.

Assad’s government quickly accepted the broad proposal, but there have been tough negotiations on how its stockpile will be destroyed.

Security Council action on Syria had long been stalled because of differences between Russia and China, who back Assad’s government, and the U.S., Britain and France, who support the opposition. Russia and China have vetoed three Western-backed resolutions aimed at pressuring Assad to end the violence.

Work on the new resolution continues while the Organization for the Prohibition of Chemical Weapons, the body that will be in charge of securing and destroying the stockpile, is working on its own document to set out its exact duties. The U.N. resolution will include the text of the OPCW’s declaration and make it legally binding — so the OPCW must act first.

The Hague-based OPCW said Thursday it was optimistic it could quickly schedule a meeting of its 41-nation executive council to approve a roadmap for swiftly destroying Syria’s chemical arsenal and production facilities.

A U.N. diplomat, speaking on condition of anonymity because consultations have been private, said the executive board of the OPCW isn’t likely to meet before Sunday, which means that Security Council adoption of the resolution likely won’t take place until next week.